Mitsubishi Electric PQHY-P72TYHMU-A Service Handbook page 177

[ VII Control ]
(3) BC controller (cooling only, heating only, cooling main and heating main modes)
Protection function
self-holding cancelled.
Fan
Solenoid valves OFF
LEV Fully closed
Cooling Only
Note 1. The system may go into the error mode on either the indoor unit side or the BC controller or heat source
unit side. If some of the indoor units are experiencing a problem, only those indoor units that are
experiencing the problem will stop. If the BC controller or the heat source unit is experiencing a problem,
all the connected units will stop.
HWE09080
Start
NO
Breaker
turned on
YES
NO
Operation
command
YES
1. Determination of operation mode
(Cooling only, Heating only, Mixture
of units in cooling and heating)
2. Transmitted to the heat source unit
Reception of operation mode
command from the heat source unit
*Note 1
YES
Error mode
NO
Mixture of units in cooling and heating
Operation
mode
All units in the
Operation
same mode
mode
Operation
mode
Heating Only
Cooling Main
3
- 168 -
Normal operation
Error
Unit in the stopped state
Error command to
heat source unit
Error stop
Self-holding of
protection function
Error command to
Heating Main indoor unit
GB